JPH02214703A - Method for gas-phase polymerization of alpha-olefin, controlled by simultaneously adding activator and activity retarder to polymerization medium - Google Patents

Abstract

A process for controlling the continuous gas-phase polymerisation of one or more alpha-olefins in a fluidized and/or mechanically stirred bed reactor using a high activity catalyst based on a transition metal of groups IV, V or VI of the Periodic Table comprises introducing into the reactor, continuously and simultaneously, an activity retarder and an activator, in very small amounts, in a molar ratio and at flow rates which are varied with time in order to maintain substantially constant either the polymerization rate or the transition metal content of the polymer produced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application] The present invention relates to the gas phase polymerization of α-olefins in a fluidized and/or mechanically stirred bed reactor in the presence of a transition metal-based catalyst. Concerning how to do.

[Conventional technology and lesson 1! ] In the presence of a catalyst based on a transition metal belonging to groups IV, V or VI of the periodic table of the elements, in particular in the presence of a catalyst of the Ziegler-Natta type or a catalyst based on chromium oxide, the fluidized and / or in a mechanically stirred bed reactor;
it or multiple α- such as ethylene or propylene
It is known to polymerize olefins continuously in the gas phase. The polymer particles in the forming step are maintained in a fluid and/or agitated state in a gas phase reaction mixture containing one or more alpha-olefins to be polymerized, which is continuously introduced into the reactor. .

The catalyst is introduced into the reactor continuously or intermittently, but
The polymer constituting the fluidized and/or mechanically stirred bed is likewise continuously or intermittently withdrawn from the reactor. The heat of the polymerization reaction is primarily removed by the gaseous reaction mixture, which is recycled to the reactor. before passing through a heat transfer means.

When carrying out the gas-phase polymerization process of α-olefins in the presence of highly active catalysts, small fluctuations are observed during the polymerization, e.g. due to slight fluctuations in the catalyst used in the reaction or in the quality of the α-olefins. However, this can cause variations in the kinetic behavior and activity of the catalyst as well as the active polymer particles forming the bed. These small fluctuations are known to have particularly adverse effects in gas phase polymerization processes. This is due to the fact that the heat exchange capacity of the gas phase is much smaller than that of the liquid phase. In particular, they cause an unexpected increase in the amount of heat released by the reaction, which is difficult to predict. - In general, this heat can be removed sufficiently quickly and efficiently by the gas phase reaction mixture passing through the bed, not only can it cause the formation of hot spots in the bed, but also cause agglomeration of the molten polymer. Cause the formation of things. Once hot spots appear in the bed, it is generally too late to avoid agglomerate formation. However, reaction conditions should be calibrated early enough to limit the adverse effects of unexpected overreactions, especially by lowering the polymerization temperature or pressure, or by reducing the feed rate of catalyst to the reactor. If this is achieved, the amount and size of the aggregates formed can be reduced to a certain extent.

However, during this time it is impossible to avoid a decline in the quality of polymer production and the produced polymer.

As a result, if it is desirable to avoid these disadvantages,
General polymerization conditions are usually selected with a safety margin so that hot spots and agglomerates cannot form.

However, the application of conditions of this type does not inevitably result in a substantial reduction in production or in the quality of the polymers produced, in particular an increase in the content of catalyst IIx residues in the polymers.

These overactivation phenomena are particularly prone to occur when using high yield catalysts where small variations in the proportion of impurities in the polymerization medium can significantly change the polymerization activity. This is a Ziegler film based on magnesium, a halogen and a transition metal such as titanium, vanadium or zirconium.
This is particularly the case with Natta type catalysts. This type of overactivation phenomenon also occurs when comonomers capable of activating the polymerization of α-olefins are used, especially in the case of copolymerizations of ethylene with α-olefins containing from 3 to 8 carbon atoms. Obtain (PolymerScience U
SSR, vol, 22.1980, No. 448-45
4 pages).

Also, European Patent Application Nos. 99.774 and 2
No. 57,316, it is known to polymerize propylene using a Ziegler-Natta type catalyst in a fluidized bed reactor, in which an organoaluminum compound as a cocatalyst and a selectivity The aromatic ester as regulator is introduced continuously at a constant rate and in a constant molar ratio to the catalyst. Furthermore, by adjusting the ratio of the amounts of cocatalyst and selective reagent introduced into the reactor, the isotacticity of the polypropylene produced by this method can be adjusted. By a model that uses the productivity of the catalyst to calibrate the isotacticity of the polymer.

However, this method and the model used can affect the polymerization rate, polymer production, and even production if the quality of the reactants, activity of the catalyst, or feed of catalyst to the reactor changes unexpectedly during the polymerization. However, it is not possible to maintain a constant transition metal content in the polymer.

We have now discovered a method for gas phase polymerization of α-olefins that makes it possible to overcome the above-mentioned drawbacks.

In particular, this method provides high productivity and low catalyst residue content, giving normal results with unavoidable slight fluctuations in the quality of the α-olefin or catalyst or in the feed of catalyst to the reactor. This enables continuous production of polymers.

It has been found that by this method it is now possible to continuously produce polymers of substantially constant and sufficient quality, without the formation of drugs, and giving a high degree of reproducibility and high yields.

[Means for Solving the Problems] Therefore, the present invention uses a catalyst based on a transition metal belonging to group IV, V or VI of the periodic table of the elements in the presence of an activator and an activity retardant. When performing continuous gas phase polymerization of one or more α-olefins in a fluidized and/or mechanically stirred bed reactor, an activator and an activity retardant are added to the reactor in very small amounts during the polymerization. one or more α-olefins, characterized in that they are introduced continuously and simultaneously in molar ratios and flow rates that vary over time to maintain a substantially constant polymerization rate or transition metal content of the polymer produced; Concerning a continuous gas phase polymerization method.

The activity retarder is preferably a gas or a volatile liquid under the polymerization conditions and is selected from a wide variety of products capable of reducing the rate of polymerization of alpha-olefins in the presence of transition metal-based catalysts. do. Activity retarders can be selected in particular from polymerization inhibitors or from poisonous substances known for reactions of this type. Particularly suitable activation retardants include carbon monoxide, carbon dioxide, carbon disulfide, carbon oxysulfide,
These include nitrogen oxides and peroxides, oxygen, alcohols, aldehydes, ketones, thiols and water. The activity retarder is also selected from electron donor compounds capable of complexing the catalyst and reducing the polymerization rate, in particular from organic compounds containing at least one oxygen, sulfur, nitrogen and/or phosphorus atom. be able to. It can be selected from a wide variety of electron donor compounds such as amines, amides, phosphines, sulfoxides, sulfones, esters, ethers or thioethers.

Activity retardation in an amount that can reduce the rate of polymerization without substantially affecting the quality and properties of the polymer produced, such as the melt index, melt flow rate, average molecular weight, molecular weight distribution, or isotacticity of the polymer. It is particularly recommended to use agents. Indeed, it is an important principle of the present invention that the rate of introduction of the activity retarder into the reactor can vary over time, so that the properties of the polymer produced are
If the amount of activity retarder used substantially affects the properties of the polymer, it can vary significantly during the course of the reaction.

This kind of result is contrary to the purpose of the present invention.

However, from the point of view of the conditions under which reaction retarders are used in the present process, especially when small amounts are introduced into the reactor, the selection of the retarder may be difficult, such as polymerization inhibitors and electron donor compounds. Can still be made from a large number of products.

Conventional polymerization poisons, preferably alcohols, carbon monoxide, carbon dioxide or oxygen, as well as electron donor compounds, preferably amides and aliphatic or cyclic ethers having up to 10 carbon atoms can be used. If the polymer produced is of stereospecific nature, such as polypropylene, the activity retarders are preferably selected from among the conventional polymerization poisons or inhibitors, as well as selectivity modifiers, such as aromatic esters. Select from among the electron donor compounds considered as

The activity retarder can be used in pure form, preferably diluted with a gas such as nitrogen, or dissolved in an easily volatile liquid hydrocarbon. Furthermore, it is possible to use mixtures of two or more activity retarders.

The activators used according to the invention are preferably gaseous or volatile liquids under the polymerization conditions and can be of a wide variety of types capable of increasing the polymerization rate of alpha-olefins in the presence of transition metal-based catalysts. products to choose from. The activator can be selected from organometallic compounds of metals belonging to groups I, II or III of the Periodic Table of the Elements, in particular organoaluminum, organozinc or organomagnesium compounds.

Preference is given to using organoaluminum compounds, especially triethylaluminum, diethylaluminum chloride, tri-n-globylaluminum, tri-n-butylaluminum and triisobutylaluminum.

The activator can be used in pure form or preferably diluted with gas or diluted or dissolved with readily volatile liquid hydrocarbons. It is also possible to use more than one activator.

According to the present invention, it has been recognized that the activator and the activity retarder should be introduced sequentially and simultaneously into the polymerization reactor. In fact, they are introduced into the reactor at the same time as the alpha-olefin or alpha-olefins, continuously or nearly continuously, in an intermittent manner, so that downtimes are short and substantially constant. It shall not affect the polymerization rate to be maintained.

If the introduction of the activator and activity retardant is interrupted, or if the interruption time is not prolonged, the activity of the catalyst may change; the polymerization rate is no longer regulated and changes rapidly with the quality of the reactants and catalyst. This results in the formation of aggregates.

The activator is added to the reactor so that the molar ratio of the amount of activator introduced to the amount of α-olefin(s) introduced is from 10-7 to 10-4, preferably from 2X10-7 to 5X10-S. It was recognized that it should be introduced in small quantities. In order to minimize the amount of activator, it is important to ensure a constant introduction to the reactor, ie a minimum rate of introduction of activator into the reactor. The amount of activator generally depends on the type of gas phase polymerization system used and the type of catalyst used. The minimum amount of activator to be used, and therefore the minimum flow rate of activator introduction into the reactor, can be easily determined by the minimum value of catalyst activity that will give the desired quality of the polymer produced. can.

Additionally, the maximum amount of activator available for use, and therefore the maximum flow rate of activator introduction into the reactor, is determined directly by the maximum heat exchange of the gas phase polymerization system or by the maximum polyolefin production without inducing the formation of aggregates. be done.

Also, the activity retarder is generally introduced continuously into the polymerization reactor in such small quantities that it is impossible to measure the proportion of this retarder in the gaseous reaction mixture circulating through the reactor. In fact, the activity retardant can be used to increase the molar ratio of the amount of activity retarder introduced to the amount of alpha olefin or alpha olefins introduced from 10-8 to 1 Ω-
5, preferably 5 x 10-1' to 2 x 10-'
into the reactor in an amount such that: Surprisingly, to continuously produce polyolefins of constant quality without the formation of agglomerates, giving high productivity and a high degree of reproducibility, the introduction of a minimal amount of activity retarder into the reactor It has been recognized that there is a need to ensure a minimum rate of introduction of the activity retarder into the reactor. This surprising result is observed especially when the process is carried out in large-scale industrial reactors using substantial volumes of gas during the polymerization.

The amount of activity retarder generally depends on the type of gas phase polymerization system used and the type of catalyst used. The minimum amount of activity retarder to be used and therefore the minimum flow rate of activity retarder introduction into the reactor is readily determined by the maximum heat exchange of the gas phase polymerization system or by the maximum polyolefin production without inducing the formation of agglomerates. be able to. Additionally, the maximum amount of activity retarder to be used and therefore the maximum flow rate of activity retarder introduction into the reactor is determined by the maximum concentration of gases and impurities that can be introduced into the reactor by the reactants if the quality of the reactants varies. It can be determined directly by the value.

In particular, if the minimum rate of introduction of the activity retarder is too small,
It has been observed that upon polymerization, polymer production can drop significantly to such a level that the introduction of the activity retarder must be stopped. In this case, a reduction in production may become inevitable and the content of catalyst residues in the polymer may increase significantly. Advantageously, this disadvantage is easily alleviated by the fact that the activator is introduced into the reactor continuously and the rate of its introduction can be increased.

Also, if the rate of introduction of the activity retarder is too high, i.e. the amount of activity retarder introduced versus the α or α
- If the molar ratio of the amounts of olefins is excessive, the polymer production decreases or the content of catalyst bottoms in the polymer can increase significantly. Additionally, excessive amounts of activity retarder can give a non-uniform gaseous reaction mixture, leading to difficulties in controlling the polymerization rate.

According to the invention, it is further necessary to vary the molar ratio of the amounts of activator and activity retardant introduced, as well as the rate of introduction of these two alternatives over time, which may affect the quality of the reactants or catalyst. , or in the case of slight fluctuations in the feed of catalyst to the reactor, it is recognized that a substantially constant polymerization rate should be maintained if the amount of polyolefin produced per hour is less than 5% by weight. It was evaluated that the polymerization rate was found to be substantially constant over time if it did not vary by more than 3% by weight, preferably by more than 3% by weight.

In another iw of this process, the rate of introduction of the activator and the activity retardant and the molar ratio of the amounts of the two reagents introduced are varied over time to improve the quality of the reactants or catalyst during the polymerization or It has been found that it is possible to maintain a substantially constant content of transition metal in the polymer produced when the feed of catalyst to the reactor is varied. It was assessed that this content was considered to be substantially constant if it did not vary by more than 5%, preferably by more than 5%.

Gas phase polymerization processes generally depend on operating conditions such as partial pressures of the major components of the gaseous reaction mixture, total pressure, catalyst feed rate, fluidized bed height or weight, polymerization temperature, gas velocity, and polymer withdrawal rate. Under such conditions, the rate of polymerization can be readily determined by maintaining it substantially constant. This applies directly to polymer production (i.e., to the polymer withdrawal rate), or to the α-olefin feed rate, or to the difference between the inlet and outlet gas temperatures of the fluidized bed. This is because they are correlated.

Therefore, for example, if it is recognized that polyolefin production tends to increase during polymerization, or if it is recognized that the content of transition metals in the produced polymer tends to decrease (introduced into the reactor), (due to an unexpected drop in the impurity of the alpha-olefin or alpha-olefins, or due to the use of a new catalyst with slightly higher activity than the previous one, or due to a higher than planned feed of catalyst to the reactor), an increase in activity retardant The rate of introduction is increased, the rate of polymerization is kept constant, and in particular the polymer production or the transition metal content in the produced polymer is kept constant. If the rate of introduction does not vary, or if this variation is very small, the retrograde effects of overactivation occur quickly, with the appearance of hot spots and aggregates in the bed; on the other hand, the introduction of the activity retarder If it is intended to avoid an excessive increase in the rate of , the amount of active agent introduced can advantageously be reduced.

Conversely, if it is observed that polyolefin production tends to decrease during polymerization, or if it is observed that the content of transition metals in the produced polymer tends to increase, the activation retarder should be It has been recognized that the rate of introduction should be reduced in order to maintain a constant rate of polymerization, particularly the polymer production, or the content of transition metal in the polymer produced. If the rate of introduction does not vary, or if this variation is very small, the polymer production inevitably decreases and the content of transition metals in the polymer increases. If, as a result of this variation in the rate of introduction, the amount of activity retardant introduced is reduced to its minimum level, the rate of introduction of the activator is increased to an appropriate value to reduce the rate of polymerization or the polymer produced. It is recommended to maintain a constant content of transition metals.

Surprisingly, it has been found that by virtue of the present invention, gas phase polymerizations can be carried out at higher temperatures and under higher α-olefin pressures than previously possible. One unexpected advantage of this method is that polyolefin production can be increased by up to 25% and the risk of hot spots and agglomerate formation can be substantially reduced with zero time. It is now possible to produce polyolefins of excellent quality with a high degree of reproducibility through the continuous introduction of variable amounts of activators and activity retardants, which depend on the quality of the reactants, the activity of the catalyst, Surprisingly, the antagonistic effects of activator and activity retarder on the polymerization rate do not directly exert themselves, but cancel each other out. They do not fit together, but give an overall effect that is different from what would normally be expected from the mere juxtaposition of their respective effects. In fact, the effects exerted by the two reagents were found to appear with different intensities and time lags.

More specifically, the effects provided by active agents develop relatively slowly over time, whereas those provided by activity retardants appear almost immediately. Thus, the gas phase polymerization of α-olefins can be controlled under improved conditions by combining the specific use of these two reagents. the quality of the reactants or catalyst, or the reactor, which is coarsely set and then regulated by a precise and appropriate selection of the rate of introduction of the activity retarder, which makes it possible to achieve the desired level of production. If unexpected fluctuations occur in the supply of catalyst to the catalyst, first modify the rate of introduction of the retarder,
If this initial modification is then found to be insufficiently effective, by modifying the rate of introduction of the active agent,
The polymerization rate can be kept constant.

Another unexpected advantage of the present invention is that the polyolefin thus produced has a significantly reduced transition metal content;
Furthermore, the result is that it has excellent quality and does not form agglomerates. Other advantages of this method are that the control of polymerization is not accompanied by measurements of activator and retarder in the polymerization medium, polymer production can be directly controlled via the rate of introduction of the retarder, and the gas phase This stems from the fact that all other operating conditions of the polymerization remain essentially unchanged.

This method also generally allows the use of very high yields of catalysts whose polymerization activity is particularly sensitive to slight variations in the polymerization conditions. These catalysts can be introduced into the reactor continuously or intermittently. It is possible to use more active catalysts, in particular catalysts of the Ziegler-Natta type based on magnesium, halogens, titanium and/or vanadium and/or zirconium. Also, by adding relatively large amounts of co-catalysts, usually selected from organometallic compounds of metals belonging to groups ■, II or III of the Periodic Table of the Elements, in particular organoaluminum, zinc and organomagnesium compounds. , can increase the activity of these catalysts.

The cocatalyst may partially activate the Ziegler-Natta type catalyst before introduction into the reactor, which may be the same or different from the activator used in the process. Modifiers can also be used with Ziegler-Natta type catalysts. The modifier is an electron donor compound,
More particularly, it can be a selective regulator such as an aromatic ester or a gael compound (which is continuously introduced into the reactor at a constant rate and in a constant molar ratio together with the catalytic transition metal). The modifier can be the same or different from the activity retardant used in the method.

It is also based on refractory oxides such as silica, alumina or aluminum silicate, and is heated to at least 250°C.
and at most a temperature at which the granular support can begin to sinter;
Highly active catalysts based on chromium oxide associated with activated granular supports can be used, preferably by heat treatment at temperatures between 350 and 1000°C. It can be contacted with an organometallic compound. Organometallic compounds are I and I of the periodic table of elements.
It has a metal belonging to Group I or III and can be the same or different from the activator used in the method.

Highly active catalysts can thus be used directly or in the form of prepolymers. Conversion to a prepolymer is generally carried out by contacting the catalyst with one or more alpha-olefins in an amount such that the prepolymer contains from 0.002 to 10 mmol of transition metal per duram; and periodic table of elements, II or I
An organometallic compound of a metal belonging to Group II can be brought into contact with an organometallic compound, in which case one of the metals in the organometallic compound
The molar ratio of the amount of transition metal to the amount of transition metal is 0.1 to 50, preferably 0.
, 5 to 20. Organometallic compounds are
The active agent can be the same or different from the active agent used in the method. The highly active catalyst used directly or after the prepolymerization step is introduced into the reactor continuously or intermittently.

Polymerization is carried out in a fluidized and/or mechanically stirred bed reactor.
By known techniques, for example French patent no. 220714
5 or FR 2 335 526, this process is extremely difficult to carry out, in which minimal fluctuations in the polymerization rate can very quickly lead to retrograde effects such as the formation of aggregates. Particularly suitable for large industrial reactors, the gaseous reaction mixture containing one or more α-olefins subjected to polymerization is generally 1. The activity retarder is cooled by at least one heat exchanger placed outside the reactor before recycling through the recycle line, preferably in a reactor in which the activity retarder is rapidly dispersed. zone, for example directly at the bottom of the fluidization grid. It can also be introduced into the line that recycles the gaseous reaction mixture or into the line that feeds the reactor with the alpha-olefin. a means for the recycle line to separate the gas from the solid particulates carried along with the gas, such as a cyclone;
If means are provided for recycling these particulates into the polymerization reactor, the activity retarder can be introduced at any point in the gas/solid separation means or in the means for recycling the particulates. Preferably, it may be introduced into the recycle line upstream of the heat exchanger. It can also be introduced into the catalyst supply line. The activity retardant is the 2nd phase of the polymerization system.
It can be advantageously introduced at the above points.

The activator is introduced into the reactor separately from the activity retarder. It can be introduced directly into the reactor, preferably in a zone of the reactor where the activator is rapidly dispersed, especially in the lower part of the fluidization grid. It can also be introduced into a line that recycles the gaseous reaction mixture, but also into a line that supplies readily volatile liquid hydrocarbons or liquid alpha-olefins to the zero reactor upstream or downstream of the heat exchanger. can also be implemented.

The polymerization reaction is generally carried out at a pressure of 0.5 to 5 HPa and 0
This process, carried out under temperatures of ~135° C., is suitable for the polymerization of one or more α-olefins containing 2 to 8 carbon atoms, especially of ethylene or propylene.

This applies to the copolymerization of ethylene and at least one α-olefin containing from 3 to 8 carbon atoms, or propylene and at least one α-olefin containing from 4 to 8 carbon atoms, if appropriate using ethylene and/or non-conjugated dienes. at least one α containing
- Particularly suitable for copolymerization with olefins. This gaseous reaction mixture may contain hydrogen and an inert gas selected from, for example, nitrogen, methane, ethane, propane, butane, isobutane, pentane, impentane or hexane. Fluidized bed.

If a reactor is used, the flow rate of the gaseous reaction mixture through the bed is 2 to 10 times the minimum flow rate. The produced polymer is withdrawn from the reactor continuously, preferably intermittently.

[Example] Takumi 1 The process was carried out in a fluidized bed reactor for gas phase polymerization consisting of a vertical cylinder 0.9 m in diameter and 6 m in height mounted by a calming compartment. The reactor is equipped with a fluidization grid in its lower part and an external line of recycle gas, which connects the top of the calming compartment and the bottom of the reactor at a point below the fluidization grid. The recycle line comprises a recycle gas compressor and heat transfer means. In particular, ethylene,
The line supplying budo-1-ene, hydrogen and nitrogen is
Shows the main components of the gaseous reaction mixture passing through the fluidized bed and connecting to the recycle line.

At the top of the fluidization grid, the reactor is 0.711
The fluidized bed consists of 400 kQ of linear low density polyethylene powder consisting of particles with a weight average diameter of 1.

The gaseous reaction mixture was 30% ethylene, 12% boudo-1-ene, 6% hydrogen, 51% nitrogen and 1% by volume.
of ethane and passed through the fluidized bed at a pressure of 1.6 HPa, 80° C. and an upward flow rate of 0.5 w/s.

The same catalyst as described in Example 1 of FR 2 405 961 is introduced intermittently into the reactor. The catalyst contains magnesium, chlorine and titanium, with 40 g of polyethylene per mmol of titanium and a predetermined amount of tri-n-octylaluminum (TnOA) (AI/T).
Assume that the molar ratio of i is equal to 1.10±O, OS)
The rate of introduction of the prepolymer into the reactor is 0.6 ko/h.

During polymerization, dimethylformamide (
DHF) solution (0.004 mol DHF per liter)
) is continuously introduced into the line for recycling the gaseous reaction mixture at a point located downstream of the heat transfer means. At the same time, a solution of trimethylaluminum (TEA) in n-hexane (0.1 mol TEA per liter)
) is continuously introduced into the line for recycling the gaseous reaction mixture from a point located upstream and in the vicinity of the heat transfer means. A copolymer of ethylene and budo-1-ene having a density equal to 0.918
Manufactured at a speed of 0±3k (If).

The production is maintained at this value throughout the polymerization by the introduced DMF solution and the IE^ solution, and for most of the polymerization time,
2101/h and 330 ml/h of these, respectively.
Adjust to the average speed of h.

Under these conditions, in continuous polymerization over several days,
No aggregate formation was observed. Furthermore, the copolymer produced by this method has a weight of about 7 tlEl
of titanium, and unpredictable fluctuations in impurities introduced by the constituents of the gaseous reaction mixture and random fluctuations in the activity of the prepolymer (the molar ratio ^l/Ti is approximately 1.0
(varies between 5 and 1.15), but has a constant quality. Furthermore, throughout the polymerization, the ratio of carbon monoxide and carbon dioxide in the ethylene fed to the reactor is approximately 0.01 to 0.0591, respectively, by volume.
) and were found to vary between approximately 0.1 and 0.5 vp+i. During the course of the polymerization, where the ratio of carbon monoxide and carbon dioxide was the lowest, it was necessary to increase the rate of introduction of the DHF solution to 300111/h in order to maintain constant copolymer production. Conversely, while the carbon monoxide and carbon dioxide ratios were at their highest, it was necessary to reduce the rate of introduction of the DMF solution to 80111/h in order to maintain a constant copolymer production. Also, for relatively short periods of time, the ratios of carbon monoxide and carbon dioxide in the ethylene fed to the reactor are 0.1 vpm and t
increased to van. During this period, the rate of introduction of the DHF and TEA solutions was set at 370 ml/h and 660+I/h, respectively, in order to keep the copolymer production constant.

If the quality of ethylene changes during the polymerization, the molar ratio of the amount of DHF introduced to the amount of ethylene and but-1-ene introduced is adjusted within the range of 0.9 x 10-7 to 4 x 10-'. It is necessary to modify the molar ratio of the amount of TEA introduced to the amount of ethylene and budo-1-ene introduced to 0.
It was necessary to modify within the range of 9 x 10-s to 1.8 Xl0-'.

1 animal except for using tetrahydrofuran instead of DHF.
The process was carried out under exactly the same conditions as described in Example 1.

In a manner similar to that of Example 1, a copolymer of ethylene and budo-1-ene is obtained.

The process was carried out under exactly the same conditions as described in Example 1, except that the DHF and TEA solutions were not introduced.

The yield of linear low density polyethylene fluctuated with time within the limits of less than 97 kQ per hour and greater than 103 kQ per hour, and upon copolymerization it was immediately observed that aggregates of molten M polymer were formed. .

Claims (10)

[Claims] (1) in a fluidized and/or mechanically stirred bed reactor using a catalyst based on a transition metal belonging to groups IV, V or VI of the Periodic Table of the Elements in the presence of an activator and an activity retarder. ,1
Or, when performing continuous gas phase polymerization of multiple α-olefins, during the polymerization, an activator and an activity retardant are continuously and simultaneously added to the reactor in very small amounts at a molar ratio and rate that vary over time. 1. A process for the continuous gas phase polymerization of one or more α-olefins, characterized in that a substantially constant polymerization rate or transition metal content is maintained in the polymers introduced and produced. (2) The molecular ratio of the amount of activity retarder to be introduced to the amount of one or more α-olefins to be introduced is 10^-^8 to 10^
2. A process according to claim 1, characterized in that the activity retarder is introduced into the reactor in an amount such that -^5. (3) Amount of activator introduced versus α or αs introduced
-The molecular ratio of the amount of olefin is 10^-^7~10^-^
2. Process according to claim 1, characterized in that the activator is introduced into the reactor in an amount such that: 4. A method according to claim 1, characterized in that the activity retardant is selected from polymerization inhibitors and electron donor compounds. (5) The polymerization inhibitor is selected from carbon monoxide, carbon dioxide, carbon disulfide, carbon oxysulfide, nitrogen oxides and peroxides, alcohols, thiols, aldehydes, ketones, oxygen and water. The method according to claim 4. (6) The electron donor compound is selected from amines, amides, phosphines, sulfoxides, sulfones, esters, ethers and thioethers.
Method described. (7) The method according to claim 1, characterized in that the activator is an organometallic compound of a metal belonging to Group I, II or III of the Periodic Table of the Elements. (8) The method according to claim 7, wherein the organometallic compound is an organoaluminium, organozinc or organomagnesium compound. (9) The process according to claim 1, characterized in that the catalyst is a Ziegler-Natta type catalyst based on magnesium, halogen, titanium and/or vanadium and/or zirconium. 10. Process according to claim 1, characterized in that the catalyst is based on chromium oxide, accompanied by a granular support based on a refractory oxide, and activated by heat treatment.